Preparation method for selectively growing lead sulfide film on surface of patterned substrate

Abstract

The invention discloses a preparation method for selectively growing a lead sulfide film on the surface of a patterned substrate. The preparation method comprises the following steps: 1) placing the patterned substrate in an oxidant solution for surface modification; 2) spin-coating photoresist on the surface of the patterned substrate, performing maskless exposure and photoresist removal, and circulating for multiple times; and (3) putting the patterned substrate subjected to surface pretreatment into the precursor solution for growing the lead sulfide film, and carrying out chemical deposition reaction. According to the preparation method provided by the invention, the lead sulfide film can be selectively grown on the substrate containing the metal pattern by simply treating the surface of the substrate without changing the proportion or condition of a deposition solution, so that complicated and expensive epitaxial layer thinning, etching and other procedures in the subsequent chip manufacturing process are avoided; according to the preparation method, the defect that film growth can only be carried out on the whole lead sulfide film at the same time when the lead sulfide film is grown through a chemical bath method is overcome, the technological process is greatly simplified, and the success rate and the yield of detector preparation are improved.

Description

Technical Field

[0001] The invention belongs to the technical field of photoelectric detection, and in particular relates to a method for preparing a lead sulfide film selectively grown on the surface of a patterned substrate. Background Art

[0002] Lead sulfide is a direct bandgap semiconductor material of the IV-VI group. It is one of the earliest infrared detector materials used. It is widely used in the field of infrared detection because of its advantages such as high sensitivity in short-wave infrared, low Auger noise and room temperature operation. There are many methods for preparing lead sulfide thin films, such as electrochemical deposition, microwave heating, chemical vapor deposition, and chemical water bath deposition. Among them, the chemical water bath method has attracted widespread attention because of its easy manufacturing, low cost, no need for complex equipment, and the ability to deposit thin films on different substrates. In addition, the lead sulfide thin film synthesized by the chemical water bath method is compatible with CMOS semiconductor processes, which is conducive to the realization of low-cost, high-performance area array detectors.

[0003] Chemical bath deposition is a method for growing lead sulfide thin films based on a solution atmosphere, including two stages: nucleation and particle growth. Although the growth rate and film thickness can be controlled by adjusting the ratio of the deposition solution or the deposition environment and conditions to achieve uniform growth of the thin film on the entire substrate. However, in the preparation process of large-array lead sulfide detectors, the substrate usually includes different substances, such as electrodes and insulating substrates. The existing technology usually grows thin films directly on the surface of the entire substrate, and is unable to selectively grow thin film materials on part of the material. As a result, in the overall manufacturing process of the detector, a complex etching process is required after the thin film is grown. In this process, problems such as over-etching or incomplete etching often occur, resulting in a complex manufacturing process for the detector and a low yield, which greatly affects the performance of the detector.

[0004] If there is a method to achieve selective growth of lead sulfide thin film materials based on the chemical water bath deposition method on a metal-containing patterned substrate, the lead sulfide film can be controlled to grow only in the photosensitive area, without the need for very complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process. This is of great significance for the preparation of large-array lead sulfide detectors with excellent performance. Summary of the invention

[0005] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the main purpose of the present invention is to provide a preparation method for selectively growing a lead sulfide film on the surface of a patterned substrate, which realizes the selective growth of a lead sulfide film on the surface of a Si / SiO2 substrate and a metal layer, and can control the lead sulfide film to grow only in the photosensitive area, thereby simplifying a variety of complex and expensive processes in the subsequent chip manufacturing process, and can be widely used in the preparation of various lead sulfide-based area array detectors.

[0006] The objective of the present invention is achieved through the following technical solutions:

[0007] A method for preparing a lead sulfide film selectively grown on the surface of a patterned substrate comprises the following steps:

[0008] 1) placing the patterned substrate in an oxidant solution for surface modification to obtain a surface-modified patterned substrate;

[0009] 2) Spin-coating photoresist on the surface of the patterned substrate, performing maskless exposure and de-resisting, and repeating for multiple times to obtain a patterned substrate with a pre-treated surface;

[0010] 3) placing the patterned substrate with surface pretreatment obtained in step 2) into a precursor solution for growing a lead sulfide thin film, and performing a chemical deposition reaction to obtain a lead sulfide thin film material selectively grown on the surface of the patterned substrate.

[0011] In step 1), the surface modification time is 2-3 minutes. In this step, the surface modification time should be strictly controlled to avoid excessive damage to the Si / SiO2 substrate. The surface modification can change the hydrophilic properties of the Si / SiO2 substrate, thereby affecting the quality of the lead sulfide film grown in a chemical water bath. Furthermore, the surface modification in this step plays a very important role in the photoelectric properties of the lead sulfide photosensitive film prepared by the subsequent chemical deposition method.

[0012] In some specific embodiments, the patterned substrate is obtained by the following preparation method: 5-15nm chromium and 50-150nm gold are deposited on the surface of the Si / SiO2 substrate by magnetron sputtering, and then a metal layer is left in a local area of ​​the Si / SiO2 substrate by a photolithography stripping process to obtain a patterned substrate.

[0013] In some specific embodiments, the Si / SiO2 substrate in the patterned substrate preparation process is also pretreated, specifically: the Si / SiO2 substrate is ultrasonically treated with deionized water, acetone and alcohol for 5-15 minutes respectively, and then blown dry with nitrogen for later use.

[0014] In some specific embodiments, the oxidant is a mixture of hydrogen peroxide and concentrated sulfuric acid in a mass ratio of 7:3.

[0015] In some specific embodiments, the coating of the photoresist in step 2) is specifically to spin-coat two layers of photoresist on the surface of the patterned substrate, the first layer of photoresist is a stripping glue, and the second layer of photoresist is a UV glue.

[0016] This step involves spin coating two layers of photoresist on the surface of the patterned substrate, which may affect the wettability of the metal layer surface and change the contact angle of the metal layer surface, causing the metal layer surface to exhibit a certain hydrophobicity, greatly reducing the nucleation probability of the lead sulfide film grown by the water bath method on the metal layer surface, and inhibiting the growth of the lead sulfide film.

[0017] In some specific embodiments, the coating conditions of the first layer of photoresist are: the spin coating speed is 500-4000 rpm, and after the spin coating is completed, it is placed on a hot plate at 170°C for drying for 10 minutes; the coating conditions of the second layer of stripping glue are: the spin coating speed is 500-5000 rpm, and then placed on a hot plate at 100°C for drying for 10 minutes. This step can change the nucleation probability and growth rate of the lead sulfide film on the metal surface;

[0018] In some specific embodiments, the conditions for the maskless exposure in step 2) are: the exposure time is 8-20s; the degumming is specifically: degumming the patterned substrate after exposure, soaking it in acetone solution for 10 minutes, and then soaking it in AZ300 solution for 1-3 minutes. In this step, the soaking time should be strictly controlled to avoid damage to the substrate.

[0019] In some embodiments, the temperature of the acetone solution is 40-60°C.

[0020] In some specific embodiments, the precursor solution for growing the lead sulfide thin film is prepared by the following configuration method:

[0021] In some specific embodiments, lead acetate is configured into a 0.01-1 mol / L solution A; sodium hydroxide is configured into a 0.1-10 mol / L solution B; thiourea is configured into a 0.01-1 mol / L solution C; sodium citrate is configured into a 0.01-1 mol / L solution D; and the solution A, solution B, solution C and solution D are mixed in the order of ABCD to form a precursor solution for growing a lead sulfide thin film.

[0022] In step 4), the thickness of the lead sulfide film can be controlled by controlling the deposition time and temperature, and the uniformity of the thickness of the lead sulfide film can be controlled by controlling the angle between the immersion part and the liquid surface.

[0023] Furthermore, the conditions of the chemical deposition in step 4) are: deposition temperature is 40-60° C., deposition time is 0.5-2 h, and the angle with the liquid surface is 65-75°.

[0024] Compared with the prior art, the present invention has at least the following advantages:

[0025] 1) The preparation method provided by the present invention first modifies the surface of the patterned substrate by using an oxidant, thereby changing the hydrophilicity of the Si / SiO2 substrate, thereby affecting the quality of the lead sulfide film grown in a chemical water bath; then, by spin coating two layers of photoresist on the surface of the patterned substrate, the wettability of the metal layer surface in the patterned substrate and the contact angle of the metal layer surface are improved, that is, the affinity of the metal layer surface to water is reduced, so that the metal layer surface presents a certain hydrophobicity, thereby increasing the difference in the nucleation probability and growth rate of lead sulfide on the Si / SiO2 substrate and the metal layer surface in the patterned substrate, thereby achieving the purpose of selectively growing a lead sulfide film on a substrate containing a metal pattern, and the lead sulfide film can be accurately covered on the photosensitive area outside the metal electrode;

[0026] 2) The preparation method provided by the present invention can achieve the purpose of selectively growing a lead sulfide thin film on a substrate containing a metal pattern by simply processing the substrate surface without changing the ratio of the deposition solution or the deposition environment and conditions, and avoids the complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process; the preparation method overcomes the defect that the chemical water bath method for growing a lead sulfide thin film can only grow the thin film on the entire wafer at the same time, greatly simplifies the process flow, and improves the success rate and yield of detector preparation. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the specific embodiments of the present invention, the drawings required for use in the specific embodiments or the description of the prior art will be briefly introduced below.

[0028] Figure 1 The surface morphology of the lead sulfide thin film material deposited by chemical water bath on the patterned substrate obtained in Comparative Example 1 (measured by microscope), wherein the square area is the area where the gold substrate is located, and the rest is the SiO2 substrate;

[0029] Figure 2 The surface morphology of the lead sulfide thin film material deposited by chemical water bath on the patterned substrate obtained in Comparative Example 1 (measured by SEM), wherein (a) is the surface morphology of the lead sulfide thin film grown on the metal, and (b) is the surface morphology of the lead sulfide thin film grown on SiO2;

[0030] Figure 3 A schematic diagram of the process flow of a method for preparing a lead sulfide thin film selectively grown on the surface of a patterned substrate provided by the present invention;

[0031] Figure 4 The surface morphology of the lead sulfide film selectively grown on the surface of the patterned substrate obtained in Example 2 of the present invention (measured under a microscope), wherein the square area is the area where the gold substrate is located, and the rest is the SiO2 substrate;

[0032] Figure 5 The surface morphology of the lead sulfide film selectively grown on the surface of the patterned substrate obtained in Example 2 of the present invention (measured by SEM), wherein (a) is the surface morphology of the lead sulfide film grown on the metal, and (b) is the surface morphology of the lead sulfide film grown on SiO2. DETAILED DESCRIPTION

[0033] The present invention will be further described in detail below in conjunction with the accompanying drawings and embodiments. The following embodiments are only illustrative and not restrictive, and the protection scope of the present invention cannot be limited thereto.

[0034] When a certain amount, concentration or other value or parameter is expressed in the form of a range, a preferred range, or a preferred upper and lower numerical limit, it should be understood that it is equivalent to specifically revealing any range by combining any pair of upper range limits or preferred numerical values ​​with any lower range limit or preferred numerical value, regardless of whether the range is specifically disclosed. Unless otherwise indicated, the numerical range values ​​listed herein include the endpoints of the range, and all integers and fractions within the range.

[0035] Unless otherwise indicated, all percentages, parts, ratios, etc. herein are by weight.

[0036] The materials, methods, and examples herein are illustrative and are not to be construed as limiting unless specifically stated.

[0037] In the following examples, the index of the photoresist LOR raw material is Microchem LOR5A photoresist, which is specifically purchased from Xi'an Boyan Micro-Nano Information Technology Co., Ltd.;

[0038] The index of the photoresist S1805 raw material is DOW / Shipley S1805 photoresist, which is specifically purchased from Xi'an Boyan Micronano Information Technology Co., Ltd.

[0039] Example 1

[0040] This embodiment provides a method for preparing a lead sulfide film selectively grown on the surface of a patterned substrate. The process flow is as follows: Figure 3 As shown, it includes the following steps:

[0041] 1) Pretreatment of Si / SiO2 substrate

[0042] The Si / SiO2 substrate was ultrasonicated with deionized water, acetone and alcohol for 10 min each, then dried with nitrogen gas for later use;

[0043] 2) Preparation of patterned substrate

[0044] Depositing 10 nm of chromium and 100 nm of gold on the surface of the Si / SiO2 substrate pretreated in step 1) by magnetron sputtering, and then leaving a metal layer in a local area of ​​the substrate by a photolithography lift-off process to obtain a patterned substrate;

[0045] 3) Surface pretreatment of patterned substrates

[0046] 31) The patterned substrate obtained in step 2) is immersed in a mixture of hydrogen peroxide and concentrated sulfuric acid in a mass ratio of 7:3 for 2 minutes, then washed with deionized water, and dried with nitrogen to obtain a surface-modified patterned substrate;

[0047] 32) Spin-coating two layers of photoresist on the surface of the surface-modified patterned substrate, wherein the first layer of photoresist is a stripping glue (LOR), the spin-coating speed is 1500 rpm, and after the spin-coating is completed, it is placed on a hot plate at 170° C. and dried for 10 minutes; the second layer of photoresist is an ultraviolet glue (AZ1500), the spin-coating speed is 1000 rpm, and after the spin-coating is completed, it is placed on a hot plate at 100° C. and dried for 10 minutes to obtain a patterned substrate after the coating;

[0048] 33) performing maskless exposure on the surface of the patterned substrate after the coating, and the exposure time is 10 s;

[0049] 34) Soaking the exposed patterned substrate in an acetone solution at a constant temperature of 50° C. for 10 minutes, and then soaking it in an AZ300 solution for 3 minutes; the above steps 31)-34) are repeated twice;

[0050] 4) Prepare the precursor solution

[0051] Lead acetate is configured into a 0.20 mol / L solution A, sodium hydroxide is configured into a 0.5 mol / L solution B, thiourea is configured into a 0.15 mol / L solution C, and sodium citrate is configured into a 0.15 mol / L solution D; then, the solutions AD are mixed in the order of ABCD to form a precursor solution;

[0052] 5) Deposition of lead sulfide film

[0053] The patterned substrate with surface pretreatment in step 3) is placed in the precursor solution in step 4), the water bath temperature is maintained at 60°C, the deposition time is 0.5h, and the angle with the liquid surface is 75, so as to obtain a patterned substrate with selective growth of lead sulfide film on the surface.

[0054] Example 2

[0055] This embodiment provides a method for preparing a lead sulfide thin film selectively grown on the surface of a patterned substrate, which comprises the following steps:

[0056] 1) Pretreatment of Si / SiO2 substrate

[0057] The Si / SiO2 substrate was ultrasonicated with deionized water, acetone and alcohol for 10 min each, then dried with nitrogen gas for later use;

[0058] 2) Preparation of patterned substrate

[0059] Depositing 10 nm of chromium and 100 nm of gold on the surface of the Si / SiO2 substrate pretreated in step 1) by magnetron sputtering, and then leaving a metal layer in a local area of ​​the substrate by a photolithography lift-off process to obtain a patterned substrate;

[0060] 3) Surface pretreatment of patterned substrates

[0061] 31) The patterned substrate obtained in step 2) is immersed in a mixture of hydrogen peroxide and concentrated sulfuric acid in a mass ratio of 7:3 for 2 minutes, then washed with deionized water, and dried with nitrogen to obtain a surface-modified patterned substrate;

[0062] 32) Spin-coating two layers of photoresist on the surface of the surface-modified patterned substrate, wherein the first layer of photoresist is a stripping resin (LOR), the spin-coating speed is 4000 rpm, and after the spin-coating is completed, it is placed on a hot plate at 170° C. and dried for 10 minutes; the second layer of photoresist is an ultraviolet resin (AZ1500), the spin-coating speed is 3000 rpm, and after the spin-coating is completed, it is placed on a hot plate at 100° C. and dried for 10 minutes to obtain a patterned substrate after the coating;

[0063] 33) performing maskless exposure on the surface of the patterned substrate after the coating, and the exposure time is 15 s;

[0064] 34) Soaking the exposed patterned substrate in an acetone solution at a constant temperature of 50° C. for 10 minutes, and then soaking it in an AZ300 solution for 3 minutes; the above steps 31)-34) are repeated twice;

[0065] 4) Prepare the precursor solution

[0066] Lead acetate is configured into a 0.40 mol / L solution A, sodium hydroxide is configured into a 1.14 mol / L solution B, thiourea is configured into a 0.3 mol / L solution C, and sodium citrate is configured into a 0.3 mol / L solution D; then, the solutions AD are mixed in the order of ABCD to form a precursor solution;

[0067] 5) Deposition of lead sulfide film

[0068] The patterned substrate with surface pretreatment in step 3) is placed in the precursor solution in step 4), the water bath temperature is maintained at 40°C, the deposition time is 2h, and the angle with the liquid surface is 70°, so as to obtain a patterned substrate with selective growth of lead sulfide film on the surface.

[0069] Example 3

[0070] This embodiment provides a method for preparing a lead sulfide thin film selectively grown on the surface of a patterned substrate, which comprises the following steps:

[0071] 1) Pretreatment of Si / SiO2 substrate

[0072] The Si / SiO2 substrate was ultrasonicated with deionized water, acetone and alcohol for 10 min each, then dried with nitrogen gas for later use;

[0073] 2) Preparation of patterned substrate

[0074] Depositing 10 nm of chromium and 100 nm of gold on the surface of the Si / SiO2 substrate pretreated in step 1) by magnetron sputtering, and then leaving a metal layer in a local area of ​​the substrate by a photolithography lift-off process to obtain a patterned substrate;

[0075] 3) Surface pretreatment of patterned substrates

[0076] 31) The patterned substrate obtained in step 2) is immersed in a mixture of hydrogen peroxide and concentrated sulfuric acid in a mass ratio of 7:3 for 2 minutes, then washed with deionized water, and dried with nitrogen to obtain a surface-modified patterned substrate;

[0077] 32) Spin-coating two layers of photoresist on the surface of the surface-modified patterned substrate, wherein the first layer of photoresist is a stripping resin (LOR), the spin-coating speed is 3000 rpm, and after the spin-coating is completed, it is placed on a hot plate at 170° C. and dried for 10 minutes; the second layer of photoresist is an ultraviolet resin (AZ1500), the spin-coating speed is 5000 rpm, and after the spin-coating is completed, it is placed on a hot plate at 100° C. and dried for 10 minutes to obtain a patterned substrate after the coating;

[0078] 33) performing maskless exposure on the surface of the patterned substrate after the glue coating, and the exposure time is 20s;

[0079] 34) Soaking the exposed patterned substrate in an acetone solution at a constant temperature of 50° C. for 10 minutes, and then soaking it in an AZ300 solution for 3 minutes; the above steps 31)-34) are repeated twice;

[0080] 4) Prepare the precursor solution

[0081] Lead acetate is configured into a 0.60 mol / L solution A, sodium hydroxide is configured into a 3.0 mol / L solution B, thiourea is configured into a 0.5 mol / L solution C, and sodium citrate is configured into a 0.5 mol / L solution D; then, the solutions AD are mixed in the order of ABCD to form a precursor solution;

[0082] 5) Deposition of lead sulfide film

[0083] The patterned substrate with surface pretreatment in step 3) is placed in the precursor solution in step 4), the water bath temperature is maintained at 50°C, the deposition time is 1h, and the angle with the liquid surface is 70°, so as to obtain a patterned substrate with selective growth of lead sulfide film on the surface.

[0084] Comparative Example 1

[0085] This comparative example provides a method for preparing a lead sulfide film grown on the surface of a patterned substrate, which is basically the same as Example 2, except that step 3) is omitted, that is, the surface of the patterned substrate is not pretreated, specifically:

[0086] 1) Pretreatment of Si / SiO2 substrate

[0087] The Si / SiO2 substrate was ultrasonicated with deionized water, acetone and alcohol for 10 min each, then dried with nitrogen gas for later use;

[0088] 2) Preparation of patterned substrate

[0089] Depositing 10 nm of chromium and 100 nm of gold on the surface of the Si / SiO2 substrate pretreated in step 1) by magnetron sputtering, and then leaving a metal layer in a local area of ​​the substrate by a photolithography lift-off process;

[0090] 3) Prepare the precursor solution

[0091] Lead acetate is configured into a 0.40 mol / L solution A, sodium hydroxide is configured into a 1.14 mol / L solution B, thiourea is configured into a 0.3 mol / L solution C, and sodium citrate is configured into a 0.3 mol / L solution D; then, the solutions AD are mixed in the order of ABCD to form a precursor solution;

[0092] 4) Deposition of lead sulfide film

[0093] The patterned substrate prepared in step 2) is placed in the precursor solution in step 3), the water bath temperature is maintained at 40°C, the deposition time is 2h, and the angle with the liquid surface is 70°, so as to obtain a patterned substrate with selective growth of lead sulfide film on the surface.

[0094] Performance Test:

[0095] The present invention takes Example 2 as an example, and performs a performance test on the prepared patterned substrate with selectively grown lead sulfide thin film on the surface, and the results are as follows:

[0096] 1) Appearance

[0097] This test example tests the appearance morphology of the patterned substrates prepared in Example 2 and Comparative Example 1. The results are as follows: Figure 1-Figure 4 As shown, Figure 1 The surface morphology of the lead sulfide thin film material deposited by chemical water bath on the patterned substrate obtained in Comparative Example 1 (measured by microscope), wherein the square area is the area where the gold substrate is located, and the rest is the SiO2 substrate; Figure 2 The surface morphology of the lead sulfide thin film material deposited by chemical water bath on the patterned substrate obtained in Comparative Example 1 (measured by SEM), wherein Figure 2 (a) shows the surface morphology of lead sulfide film grown on metal. Figure 2 (b) is the surface morphology of lead sulfide film grown on SiO2; Figure 4 This is a surface morphology of a lead sulfide thin film material deposited by chemical water bath on a patterned substrate obtained in Example 2 (measured by a microscope), wherein the square area is the area where the gold substrate is located, and the rest is the SiO2 substrate; Figure 5 The surface morphology of the lead sulfide thin film material deposited by chemical water bath on the patterned substrate obtained in Example 2 (measured by SEM), wherein Figure 5 (a) shows the surface morphology of lead sulfide film grown on metal. Figure 5 (b) shows the surface morphology of lead sulfide film grown on SiO2.

[0098] contrast Figure 1 and Figure 4 , Figure 4 No such Figure 1 The silver-grey lead sulfide film shown. Figure 2 and Figure 5 , Figure 5 No formed lead sulfide grains were observed on the surface of the metal substrate, indicating that no lead sulfide material was attached. Figure 2 The uniform and dense lead sulfide grains on the metal substrate surface are in sharp contrast. The present invention changes the surface characteristics of the patterned substrate by performing special treatment on the patterned substrate surface, making the difference in the nucleation probability and growth rate of lead sulfide on the surfaces of different materials larger, thereby realizing the selective growth of lead sulfide film on the patterned substrate surface.

[0099] In summary, the present invention uses a specific solution treatment and photolithography process to simply treat the surface of the patterned substrate, so as to achieve the purpose of selectively growing lead sulfide thin films on SiO2 and metals without changing the ratio of the deposition solution or the deposition environment and conditions. The method provided by the present invention enables the lead sulfide film to accurately cover the photosensitive area and avoid the electrode area, avoiding the very complex and expensive epitaxial layer thinning, etching and other processes in the subsequent chip manufacturing process, and provides a reference value for low-cost improvement of the yield and performance of lead sulfide detectors.

[0100] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or replace some or all of the technical features therein by equivalents. These modifications or replacements do not make the essence of the corresponding technical solutions deviate from the scope of the technical solutions of the embodiments of the present invention, and they should all be included in the scope of the claims and specification of the present invention.

Claims

1. A method for preparing a lead sulfide thin film selectively grown on the surface of a patterned substrate, characterized in that: The steps include: 1) placing the patterned substrate in an oxidant solution for surface modification to obtain a surface-modified patterned substrate; 2) Spin-coating photoresist on the surface of the patterned substrate, performing maskless exposure and de-resisting, and repeating for multiple times to obtain a patterned substrate with a pre-treated surface; 3) placing the patterned substrate with surface pretreatment obtained in step 2) into a precursor solution for growing a lead sulfide thin film, and performing a chemical deposition reaction to obtain a lead sulfide thin film material selectively grown on the surface of the patterned substrate.

2. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 1, characterized in that: The patterned substrate is obtained by the following preparation method: 5-15nm chromium and 50-150nm gold are deposited on the surface of the Si / SiO2 substrate by magnetron sputtering, and then a metal layer is left in a local area of ​​the Si / SiO2 substrate by a photolithography stripping process to obtain a patterned substrate.

3. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 1, characterized in that: The method also includes pre-treating the Si / SiO2 substrate in the patterned substrate preparation process, specifically, ultrasonicating the Si / SiO2 substrate with deionized water, acetone and alcohol for 5-15 minutes respectively, and then drying it with nitrogen for later use.

4. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 1, characterized in that: The oxidant is a mixture of hydrogen peroxide and concentrated sulfuric acid in a mass ratio of 7:

3.

5. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 4, characterized in that: The step of coating the photoresist in step 2) is specifically to spin-coat two layers of photoresist on the surface of the patterned substrate, wherein the first layer of photoresist is a stripping glue and the second layer of photoresist is a UV glue.

6. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 1, characterized in that: The coating conditions of the first layer of photoresist are: spin coating speed is 500-4000rpm, and after spin coating, it is placed on a hot plate at 170°C for 10 minutes to dry; the coating conditions of the second layer of stripping glue are: spin coating speed is 500-5000rpm, and then placed on a hot plate at 100°C for 10 minutes to dry.

7. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 4, characterized in that: The conditions for the maskless exposure in step 2) are: the exposure time is 8-20s; the degumming is specifically: degumming the exposed patterned substrate by soaking it in acetone solution for 10 minutes and then soaking it in AZ300 solution for 1-3 minutes.

8. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 1, characterized in that: The temperature of the acetone solution is 40-60°C.

9. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 4, characterized in that: The precursor solution for growing lead sulfide thin film is prepared by the following configuration method: Lead acetate is prepared into a 0.01-1 mol / L solution A; sodium hydroxide is prepared into a 0.1-10 mol / L solution B; thiourea is prepared into a 0.01-1 mol / L solution C; Sodium citrate is prepared into a 0.01-1 mol / L solution D; The solution A, solution B, solution C and solution D are mixed in the order of ABCD to prepare a precursor solution for growing a lead sulfide thin film.

10. The method for preparing a lead sulfide thin film selectively grown on a surface of a patterned substrate according to claim 4, characterized in that: The conditions of the chemical deposition in step 4) are: deposition temperature of 40-60° C., deposition time of 0.5-2 h, and an angle with the liquid surface of 65-75°.

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